went to boca on sunday, paid 300 pesos each. here's how we did it:
got down there really early (3 hours before game), found a little restaurant/kiosko to get a drink / food, and asked the waitress if she knew how we could get tickets - instant "yes".
We had a good feeling about the place because it was filled with cops watching the San Lorenzo game, the people weren't out on street on drugs and desperate, they guaranteed that a guy would guide us into the game, and if we couldnt get in we could come back to the restaurant.
Sure it was still some risk but it worked out great.
Other notes:
felt pretty safe walking around boca stadium before and after; there are police everywhere.
the tickets were plastic season cards, with someone's picture, but they got us in fine, no idea where they got these cards (a friend? stolen? a dead guy who is now floating in rio de la plata?) but they worked great, and then they just collected them from us when we got in.
We took the subway down to catedral from palermo, and then a 25 peso taxi. to get home we walked 20 minutes north on that main road and eventually found a cab, ~40 pesos back to palermo.
Overall a great experience, we had seats in popularo sud, good view, great crowd, fun game.